function mixNamingWith(superclass) {
  return class extends superclass {
    getFullName() { 
		  return this.name + " " + this.surname;
  	}
  }
}

class ExtendedPerson extends mixNamingWith(Person) { }

var johnSmith = new ExtendedPerson("Jan", "Kowalski");

console.log(johnSmith .getFullName());		// wynik: "Jan Kowalski"
